Flow properties of a linear–gel polymer system

✍ Scribed by S. L. Rosen; F. Rodriguez

• Publisher: John Wiley and Sons
• Year: 1965
• Tongue: English
• Volume: 9
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/app.1965.070090501

✦ Synopsis

Synopsis

Flow curves (shear stress versus shear rate) were obtained for poly-(ethyl acrylate) containing up to 40% of gel particles over a range of shear rates from 3 X lo-* to 7 X 108 set.-' with a specially designed bimnical rheometer and a standard Instron capillary viscometer. Crosslink density of the gels was varied by emulsion-polymerizing ethyl acrylate 7Rith 3, 10, and 30% triethyleneglycol dimethcrylate. Particle sizes were varied by adjusting the concentration of emulsifying agent and by d i g techniques. Samples for study were prepared by blending and co-precipitating the linear and gel latices. The addition of gel always increases the shear stress at a given shear rate. However, this effect is greatest a t the lowest shear rates. The flow properties of the gelcontaining materials are related quantitatively to those of the linear material through a new parameter, the rate of viscous energy dissipation, and by two material constants. These are a yield stress and a pseudo zero-shear viscosity, both of these being functions of the amount, crosslink density, and particle size of the gel phase.